Improvement of Threshold Voltage Reliability of 4H-SiC MOSFETs With Lanthanum Silicate by High Temperature Forming Gas Anneal

We report the effect of a high-temperature forming gas anneal (FGA) on the electrical characteristics and threshold voltage (V
_T
) instability of high-mobility Si-face (0001) 4H-SiC metal oxide semiconductor field effect transistors (MOSFETs) with lanthanum silicate (LaSiO
_x
). The MOSFET with LaSiO
_x
after 800 °C FGA in 5% H
₂
and 95% N
₂
mixture shows significantly reduced V
_T
shift under 3-MV/cm positive bias stressing from 2.78 to 1.65 V, while maintaining high field-effect mobility of 122.7 cm
²
/Vs and sufficiently positive V
_T
of 2.76 V.